Luis Walter Alvarez's birth details are on astro-data-bank. Here is an attempt to understand what brought him so much success and fame. I am consciously trying to avoid to fit my analysis to what happened. The idea is to identify subtleties that change the strength of horoscope rather than ignoring negative factors and highlighting supporting factors.
Saturn is in the first house. Lagna and Saturn are almost at the same point (1 minute difference). Saturn is debilitated in the first Lagna. His ashtakavarga score in that sign is low (2). His shadbala score is low. Nevertheless, he has Neechabhanga Rajayoga (NBRY) due to two reasons. (For a neat explanation of NBRY, please read this.) 1. Saturn is exalted in D-9, well positioned with the lord of the sign (Venus). 2. Lord of the sign in which Saturn is debilitated (Mars) is in a quadrant from Moon sign. This explain, to a good extent, how he became so famous.
For Aries Lagna, the yoga karakas are Saturn (10th lord) and Jupiter (9th lord). They are aspecting each other in this horoscope. This is yet another rajayoga. Saturn is in Venus' constellation. Venus is not a benefic for Aries Lagna. Jupiter is in Rahu's constellation. Rahu has the aspect of both Jupiter and Saturn. Since he is a shadowy planet, he has the ability to give their results. Luis' best years were during Jupiter and Rahu dasas (1951-1985).
The above two rajayogas (NBRY and 9-10 lords association) clearly indicate that the native was destined to become successful, rich and famous. Apparently, these more than compensate for the Lagna Lord being in 12th house. What is not clear is how the native became such a great scientist, given that Jupiter is not so strong (in an unfriendly sign with no dikbala, debilitated in the D-9). It's a topic for another day.
Although unrelated to the main topic, it should be noted that 7th house has the aspect of Rahu and Saturn with its lord in an unfriendly sign. From Moon, 1st and 7th lords are in shashtashtaka. All of these indicate a troubled marriage. He was divorced during Rahu/Saturn dasa. Both the planets are in Venus' (functional malefic) constellation.